Magnetometry of evoked fields from human peripheral nerve, brachial plexus and primary somatosensory cortex using a liquid nitrogen cooled superconducting quantum interference device

Superconducting Quantum Interference Devices (SQUIDs) can be used to detect neuromagnetic fields evoked in the peripheral and central nervous system. Up to now, such measurements had to be based on SQUIDs with a low critical temperature (T-c) requiring liquid helium cooling. Recent improvements in high-T-c SQUID technology relying on liquid nitrogen cooling led to a significant reduction in the system's noise level. Here, first high-T-c recordings of weak neuromagnetic fields are demonstrated. In particular, along the entire somatosensory afferent pathway including peripheral nerves, brachial plexus and primary somatosensory neocortex evoked neuromagnetic activities were detected using conventional recording parameters for bandwidth and number of averages. This opens up a wide perspective for cost-effective high-T-c magnetometry in clinical neuroscience.